1. Field of the Invention
The present invention relates, in general, to a device for giving an injection of liquid medicine to a patient and, more particularly, to a controllable liquid medicine injection device capable of normally giving an injection of a predetermined amount of liquid medicine, such as a special anodyne or antibiotic, to a patient at a constant rate and selectively and temporarily allowing confluent medicine to join the primarily injected medicine, thus increasing the amount of injected medicine in accordance with a patient's condition, thus improving medicinal effect.
2. Description of the Prior Art
In the medical field, it is necessary to continuously give a special antibiotic to a person having cancer or leukemia and periodically, a special anodyne to a person suffering from post-operative pain.
In the event of special liquid medicines, such as antibiotics for sufferers of cancer or leukemia, medicine has to be normally and steadily given to a sufferer in very small amounts, which is different from general medicine. In addition, it is often required to temporarily increase the amount of injected medicine in accordance with a patient's condition. In an effort to achieve the above object, an injection hose with a manual controller is proposed. In order to control the amount of special liquid medicine passing through such an injection hose, a medical personnel, such as a doctor or a nurse, manually handles the controller while observing a controlled amount of medicine in the transparent hose. However, such a manual controller fails to precisely control the amount of liquid medicine to be given to a patient, thus forcing a medical team to repeatedly adjust the amount of medicine. Therefore, known medicine injection devices with such controllers are inconvenient to both medical teams and patients and reduce medicinal effect.
In particular, when a medical team unconsciously adjusts the manual controller to give an injection of an excessive amount of medicine to a patient, the excessive amount of medicine may cause the patient to fall into a coma or into shock death, On the contrary, when a manually controlled amount of medicine is less than an effective amount, the medicinal effect on the patient is reduced.
Sometimes, it is necessary to give another liquid medicine, such as an anodyne, to a patient when a special medicine, such as an antibiotic, is already being given to the patient using an injection hose. In this case, the other medicine or the anodyne may be directly injected into a vein using a syringe being pricked into the vein or indirectly injected into the vein with a syringe being pricked into the existing injection hose. However, the direct injection of an anodyne into a vein wastes labor of a medical team and gives additional pain to the patient, making the patient unstable. On the other hand, when the anodyne is indirectly injected into a vein with a syringe being injected into the existing injection hose, the syringe forms a syringe hole on the hose, thus causing leakage of liquid medicine from the hose through the syringe hole. Such a syringe hole may also cause infiltration of infectious bacteria into the hose. Therefore, both the injection hose and the liquid medicine have to be frequently changed with new hoses and medicine, thus being inconvenient to both a patient and a medical team.
When a liquid medicine is injected into a vein of a patient with a syringe, the amount of medicine to be injected is influenced by a pressing force applied onto the piston of the syringe so that an excessive amount of medicine may be unconsciously injected into the vein and may cause the patient to fall into a coma or into shock death.
Meanwhile, an injection pump may be used for injecting a liquid medicine into a vein of a patient. However, such an injection pump prevents the patient from moving and causes a safety alarm device of medical equipment to frequently generate a voice alarm signal, irritating to the patient and those around the patient.